The present invention relates to safety devices for motor vehicles having automatic transmissions and, more specifically, to detent means for mechanically latching the transmission selector lever in the "park" position until intentionally disengaged.
Virtually all modern-day vehicles which are equipped with an automatic transmission include means for locking the wheels against rotation by positive engagement of a member movable by the transmission selector lever, whether or not the motor is running. This is known as the "park" position of the transmission selector lever and is very frequently used by drivers as a substitute for the parking brake. That is, since moving the selector lever to "park" serves to lock the wheels against rotation, many drivers do not bother to apply the parking brake when leaving the vehicle, with or without the motor running. Of course, if the selector lever is moved to place the transmission in a forward or reverse drive position, it is possible that the vehicle may move even though the parking brake has been applied.
The dangers of having a vehicle transmission inadvertently moved out of, or not placed in, the "park" position are readily apparent. The selector lever may be inadvertently, and sometimes unknowingly, bumped by an operator or other individual in the vehicle and moved out of the "park" position after having been intentionally placed therein. Small children left unattended in a vehicle often attempt to move the transmission selector lever, which can be done in any vehicle (in most vehicles only when the engine is running) sometimes resulting in serious accidents. On other occasions an operator may leave a vehicle thinking it has been placed in "park" when in fact it has not, or the selector lever has not fully engaged in the "park" position. Some vehicles, through manufacturing defects or otherwise, have been known to move out of the "park" position after being placed therein without manipulation of the selector lever.
Locking means have been suggested for maintaining the transmission selector lever in the "park" position upon being placed therein until released through the operation of other mechanism. U.S. Pat. Nos. 3,942,614 and 4,096,930, for example, show interlock mechanisms which prevent movement out of "park" and/or neutral positions of the transmission until released by depressing the foot brake. While such mechanisms may be effective for the intended purpose, they are limited to use with rather specialized arrangements of the transmission selector mechanism and require quite extensive mechanical modifications to the vehicle for installation and operation.
It is a principal object of the present invention to provide novel and improved apparatus for locking the transmission selector lever of a motor vehicle in the "park" position, regardless of whether the motor is running or not, which is simple in construction and installation, yet reliable and durable in operation.
A further object is to provide means for releasably latching the transmission selector lever in "park" which is entirely mounted upon the exterior of the steering column.
Another object is to provide means for locking the position of the transmission selector lever in the "park" position upon movement thereto which also provide an audible and/or visual signal in response to a vehicle condition, such as opening a door or turning off the ignition switch, when the transmission is not in "park".
Other objects will in part be obvious and will in part appear hereinafter.